Poppet valve and valve seat for internal-combustion engines



July 3l 1945 w. R. BREELER ETAL 2380821 POPPET VALVE AND VALVE SEAT FOINTERNAL-COMBUSTION ENGINES Filed Jan. 21, 1941 AfA/AL Y5/5 0. 0202/070% my. 4.0% /0 0.0% ff 7502/0 2.20%

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July-31.1945

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Pennlylvlllll e tion of aspiration :spain zi. un. sea-lai No. 31ans swl. iss-iss) our` invention relates valves and -vaive seats'for internalcombustion engines and particular-lyre which are suitable foruseinsuchvaivesandseatsoperating inengines using modern antlknock fuels.

In the drawing, ll'lg.` l is an elevation v iewofa poppet valve for sninternal combustion, engine; Fig. 2 is aplan view of a'valve seatinsert,drawn to a somewhat smaller scale than the valve in While the necessaryand desirable physical characteristics of-steels for use in Aenginevalves and seatsare well known, theproblem of finding a steel embodyingall of the necessary and most of the desirable properties is extremelydiiilcult. Three important properties are'high resistance to corrosionfrom the exhaust gases produced by modern fuels, high resistance todeformation at valve operating temperatures.- and retention of a v highdegree of hardness after prolonged exposure to these temperatures.

Poppet valves, and particularly exhaust valves. are siiected to rapidlyfluctuating stresses of great intensity while heated to elevatedtempera.-

ture by the gases resulting from the combustion Valves which are formedof steels having insufficient hot strength are subject, under theseconditions, to gradual deformation. The

vheads are forced downwardly into the seat openings until they becomeconcave or dished which changes the seat angle of the valve, preventsits closing tightly, and thus causes leakage, overheating eventually,failure. I

In order -iinaliy ivo-determine whether any steel will make asatisfactory valve the ultimate test,

A of course, requires that valves shall be made from the steel and runfor prolonged periods in'anintornai combustion engine. The manufacturingand testing of valves in this way is a long and expensive procedure, andhence it is highly desirable to devise some preliminary test to whichsamples of steel can be easily Put for the plll'DO-Sev of determiningwhether suchsteels warrant the expense of making and running .valvesmade therefrom. The valve steel problem heretofore has been largely acut and try problem. and therefore progress in developing new and bettervalve steels has been much slower than the extensively developed artotalloy steels would seem to warrant.' -It is well recognized however bythe comparatively few workers in this highly specialized nary'short-time.. hot-tensile tests, are not. ipso facto, 'suitable forinternal combustion engine Accelerated tests which fairly indicate theDrohable corrosion resistance, in actual operation, of a valve made fromsteel of a given analysis were devised a few years ago but there hasbeen nov v which hang below the furnace. At any given temperature a loadcan 'be chosen by successive trials so as to cause the strip to bend ordeiiect a-predetermined amount in a specified time. Byv

making, treating and testing all specimens exactly alike the relativeresistaices of the steels to the type of head deformation met in exhaustvalves can be accurately determined, and, if the specimens are subjected.to the test loads for 24 hours at 1400 F., this newmtesting method hasbeen found to g'ive a g0od`indication of the relative resistances of'steels to deformation in service, as determined by actual engine tests.Comparative .experiments established that the usual,v shorttime. nottensile test gives extremely unreliable indications as to the true valueoi' steels for valve service. Many steels shown to be very strong by.such tests but very weak by our accelerated creep" test failed in actualengine tests.

In our tests. all specimens were rated accord-l ing to the load inpounds required to cause a permanent bend or deection of 0.020" thereinwhen applied for 24 hours, and the numbers used hereinafter te indicatethe resistance of the various steels to hot bending are to be understoodas indicating'such load in pounds. Thus we 11nd that very weak steelsmay have ratings of less than 5.

Most of the commercial ferritic valve steels will field of research thatalloys which are' highly resistant to hot oxidation and have highstrength at elevated temperatures, as measured b y ordirange from l0 to15, and the best commercial austenitic valve steels will range from 20to 30.

No steels which we have subjected to thisftest have shown values muchover 40. l

The alloy steel from which our poppet, valves are made contains thefollowing essential alloylng elements within the ranges stated; itbeing. understood that the percentages used throughout Tnx.: I

Eject of varying chromium content Tltmdltlftqh l lc ma. Muses. simuAll'specimens werehot'worked from 17 lbs. ingots into strips andair-cooled after 30 minutes at 2000` F. The spedmens were tested forRockwell C hardness and magnetic saturation at 400 LOD-8.50 5 oerstedsiield strength,l thenheated-at 1600* F for l hour. air-cooled, reheatedat 1400 1" for lhour. and retested. They `were then subjected A .v tothe lli-hour "accelerated creep" or hot bend '5.004150 test and thehardness and magnetism again de- Balance 10 termined.

mmm u simoolsd Here is apparent the combination o! strength thespecincation and claims reier to byweight.

Per cent 0.25-1L0-0 Carbon Manganese Chromium ..ls- 18.0 A total ofelements selected from the group consisting o! manganese and nickel j'Iron Within these ranges the steel is wholly. or

nearly non-magnetic as rolled. or as quenched' 30 and hardness developedwith chromium contents from about 2.000 PL, but will become somewhat upto 20% with an abrupt drppln retained hardmsgnetic afterreheating formore or vless proness and strength with chromium contents of longedperiods at temperatures of 1200 to 1400v 22%- orV more; Themasnetic'data indicate that l'. Inpther words, the steel is neitherwholly' in the 24 and 26% chrome alloys soins of the austenitic n orwholly ierritic but betweenvthese 35 so-called "sigma phase isdeveloping as the extremcs.

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numana steels become less magnetic after reheating at the met WW1 Efe'ctof version' monash content in a 20%` @f Mn We are aware that the priorart discloses a great show that inthe absence of so nickel. the desiredcombination of strensth and retainedhardnessisattainsdonlyinaverylimited. upper portionoi our 'total desired range:(4 to 8.5% Mn) The following tab1eshows,however,thatthe formed intopppet valves of internal combustion 05 addition of nickel man! m51. g,mwen mi. and more practical range oimanganese, which is veryrimportantfrom a manufacturing stand- Ma'nganese and nickel are essentiallycomplementary in our alloy; that is, when'ths IMI-181- nese content ishigh, the nickel should be low, and vice versa. As the v approaches itsupper limit, the nickel may be omitted alto- 4 'I5 -gethen deal otinformation about steels whose principal ingredients are chromium andmanganess'but no one, so far as we are aware, has discovered thevaluable characteristics d by vsteels these elements within the ex`tremely narrow ranges -above set forth. when eneines; v the developmentoi our-steel 'a large number otexp'erlmental analyses was studied forthe purposeo! determining the particular' ranges within j which-thevarious'elements should be employed in lo order to attain the desiredresults and for the purpose of determining the enect of lvariations oi'l the elements lwithin these Tanzes. The results.oi'oin'testsoianumberofthesesteelsaretab- "ulated below.

Tseu: III

Eect of 2% nickel in steels similar to in those Table II [m/z, (1r-.0.5%c. 6.3% si, varying Mn) v Treatment (A) Treatment (n) Treatment (e)Rehm; Heat resistance Cr Mn Ni No. to hot Rock- Mag. Rock- Mag. Rock-Mag.

well sat. well sat. well sat. bending 'P-M.- I). 0 1. 0 2. 1 35 7b() 3913, N0 3Q 1B, 400 i3 t P-l.. 19. 7 4.1 2. 0 33 500 30 l0, 850 37 12, 10019' P478.. 19. 8 6. 0 2. 1 32 100 38 4, 400 39 7, 800 32 P-l79.. 19. 9B. 9 2. l 30 50 33 l, 0m 35 4, 400 lll P-180.. 19.7- 6,'1 2.1 31 50 30m0 27 150 32 P-ml.. 31.0 7. 7 2. 0 29 50 29 1w 28 150 30 P-u.. Il. 1 9.9 2. l I 29 0 29 60 27 100 32 Tur.: IV

corrosion by hot combustion products which characterizes our steels. Themaintenance of this lull contact area permits maximum flowof heat fromthe valve into the block or head, thus keeping the valve moderately cooland reducing corrosion to a minimum. Under the same conditions s. weakervalve might deform by dish- Eect o! adding nickel to a I% chromium-6%manganese alloy [0.5% carbon, 0.3% silicon] i There is, evidently, noadvantage in nickel contents which are higher than those needed to givethe best strength, magnetic and hardness properties; but it will benoted that 1% nickel has made a great and valuable change in thecharacter of the 6% manganese alloy. This steel appears to behaveexactly like those containing 5% manganese and 2% nickel or the plain 8%manganese steels. In other words, small quantities of nickel whencombined with manganese appear to be the equivalent of additionalmanganese in producing a steel having our desired properties.

The foregoing data reveal conclusively that there exists a narrowcomposition range within whichsteels may be made which are uniquelyqualified to withstand the punishment borne by the exhaust valves ofmodern internal combustion engines. These steels develop a degree ofhardness which is moderate but sufficient to withstand the wearingaction on the valve stem and tip, and, moreover, this hardness -isretained after heating to valve operating temperatures so that the seatportion of the head remains suillciently hard to resist the indentingaction of hard particles which may be trapped between the valve head andits seat. Our steels are strong at valve operating temperatures and willwithstand the stresses developed in operation. Thus, the originalcontact area between the valve head and seat in the cool engine block orhead ol the motor is maintained. This last mentioned feature is animportant factor in the superior resistance to ing" down through thevalve port, thus' changing the seat angle and reducing the contact area.In such a case the valve overheats to such a degree that even the mostcorrosion-resistant materials fail.

Many investigators, heating chromium-manganese steels in air or oxygen,have found that they are more heavily scaled than chrome-nickel or plainchromium steels and have therefore conl cluded that they were unsuitedfor service at elevatedtemperatures.

modern internal combustion engine valves is prin- However, the corrosionof cipally due not, to oxygen but to the products resulting from thecombustion of fuels. These products form a deposit on the valves whichattacks the hot metal. Many tests have demonstrated thatchromium-manganese steels, either with or without small quantities ofnickel, are very resistant to such attack when the chromium content isnotl much below 20%. We have, therefore, xed the lower chromium contentof our alloy at about 18% because of the desirability of maintaininghigh resistance to such combustion' products. 'The upper chromium limit,however, is sharply defined by the abrupt decrease in strength andhardness of those steels containing chromium in quantities above about22%, as illustrated in Table I. v

Steels with less than 4% manganese are soft, weak and predominantlyferritic, as shown in Tables II and III, while manganese in quantitiesabove about 8.5% reduces the hardness and not increase the strength. i

The-maximumJ nickel content is not critical but is preferably not over4%. As discussed in connection with Tables lII and IV, a small quantityof nickel serves to eiiect a more than equal reduction in the manganesecontent, but too much nickel reduces the hardness to an undesirabledegree. essentially a chrome-manganese steel containing not less than 4%manganese with an optimum of from about 7% to 8.5% of this element.However, with manganese contents of less than this optimum, nickel,because oi' its greater eieetiveness, weight for weight, in developingthe desirable characteristic o1' our alloy, should alsobe used so thatthe total manganese plus nickel content is not less than about Thefollowing table gives some indication o! does I Thus, it may be saidthat our steel is manganese and nickel, and the balance iron; the totalquantity oi manganese in said steel being 'not less than 4% and not morethan 8.5%.

2. An internal combustion engine `valve formed of a readily i'orgeabiealloy steel characterized by vance iron; the total quantityroi'manganese in said steel being not less than 4% and not more than 8.5

3. .An internal combustion engine valve formed the e'ect of carbon: 20'of an alloy steel characterized by being essentially y Tseu: V

Effect of varying carbon in Caf- 6% Mns-2% Ni allows l 'r t t a, vTreatment (A), volgend) Tmmz' #.o'h. iw DE (n) EL 1,400" mauve Hmm. c orMn N1 1, 5 --Ff @gow nk-M.R0k-M Rock-M. wogll sa? well :4::g well wat?v.es 20.3 0.0 2.0 `2s v1.000 24 0.000 -a 3,000 s. .s4 10.0 n.0 zo a0 s0as 1,000 laus 4,400 s1 .1.14 20.3 00 2.0I 31 V100 42 1.700 44 0,400 i0 vThe minimum carbon content is obviously fixed by the comparativesoftness of the low-carbon steels while the upper limit is indicated byVThe tabulated 'data reveal that steels contain- A ing the essentialelements of our invention in the optimum proportions are essentiallynonmagnetic as rolled or as rapidly cooled from 2000'l F. but that theybecome at least moderately magnetic after prolonged reheating `at about1400*' F., which constitutes one of the distinguishing features of oursteel.

The word valve as used in the foregoing description and in the appendedclaims is to be understood as including in its meaning seat inserts forvalves and other parts'associated with valves and inserts which aresubjected in use to contact with-the exhaust. gases of an internalcombustion engine.

What we claim is:

l. An internal combustion engine valve,v formed of alloy steelcharacterized by being essentially non-magnetic as rolled, or whenquenched from about 2000** F., butwhich becomesv moderately magneticafter reheating at 1200", to 1400 F., in which condition it is highlyresistant to deformation at elevated temperatures and retains highhardness after log heating at temperatures up to 1400a F.; said steelcontaining a plurality of elements of which the following within theranges stated are then only elements necessary to attain saidcharacteristics: from 0.25% to 1.0% of carbon. from 18% to 22% ofchromium, from 5% to 8.5%v selected from the group consisting of 6% to8.5% selected from the group consisting ci manganese and nickel, and thebalance iron; the

total quantity of manganese in said steel being not less than 5% and notmore than 8.5%.

4 4. An internal combustion engine valve formed of an alloy steelcharacterized by being essentially non-magnetic as rolled, or'whenquenched from about 2000 F., but which becomes moderately magnet-icafter reheating at 1200 to 1400 F., in which condition it is highlyresistant to deformation at elevated temperatures andretains highhardness after long heating at temperatures up to 1400" F.; said steelcontaining a plurality of elements of which the following within theranges stated are the only elements necessary to attain saidcharacteristics: carbon .0.40% to 0.70%. chromium 18% to 22%, manganese7.5% to 8.5%, and the balanceiron.

5. An internal combustion engine valve formed of an-alloy steelcharacterized by being'essen-4 deformation at elevated temperatures andretains high hardness after long heating at temperatures up to 1400u F.;said steel containing a CERTIFIGATE oF coRREcTIoN.

Patent No. 2.530.821.

WALTER R. BREELER,E1.1 AL;

mation at elevated temperatures and retains high hardness after longheating at temperatures up to 1400 F.; said steel containing a pluralityof elements of which the following within the ranges stated are the onlyelements necessary to attain said characteristics: from 0.40% to 1.0% ofcarbon, from 18% to 22% of chromium, from 5% to 8.5% selected from thegroupv consisting of manganese and nickel, and the balance iron; thetotal quantityof manganese in said steel lbeing not less than 4% and notmore than 8.5%.

WALTER R. BREELER.. GURDON M. BUTLER, JR.

It is herebycertified `that'. .error appears in the printedspecification of the above numbered patent requiring Icorrection asfo11cws:'Page 5, Table opposite i page. h., Table V, seventh columnthereof', -in the heading,

"P-180",l for the numeral fer "Treatment (A) before teem", reed--Treement (B) before wenn; line line 72, 'same claim, for "then' lread--the--j and that the said letters Patent should be read with thiscorrection therein`that the same may conform. to the record of the casein the Patent Office signed'end eeelear eine 29th dey ef Jennery', A. n.19M.

Seel) Leslie Frazer F11-et VAssistentcemmieeienexor Patente.

CERTIFIGATE oF coRREcTIoN.

Patent No. 2.530.821.

WALTER R. BREELER,E1.1 AL;

mation at elevated temperatures and retains high hardness after longheating at temperatures up to 1400 F.; said steel containing a pluralityof elements of which the following within the ranges stated are the onlyelements necessary to attain said characteristics: from 0.40% to 1.0% ofcarbon, from 18% to 22% of chromium, from 5% to 8.5% selected from thegroupv consisting of manganese and nickel, and the balance iron; thetotal quantityof manganese in said steel lbeing not less than 4% and notmore than 8.5%.

WALTER R. BREELER.. GURDON M. BUTLER, JR.

It is herebycertified `that'. .error appears in the printedspecification of the above numbered patent requiring Icorrection asfo11cws:'Page 5, Table opposite i page. h., Table V, seventh columnthereof', -in the heading,

"P-180",l for the numeral fer "Treatment (A) before teem", reed--Treement (B) before wenn; line line 72, 'same claim, for "then' lread--the--j and that the said letters Patent should be read with thiscorrection therein`that the same may conform. to the record of the casein the Patent Office signed'end eeelear eine 29th dey ef Jennery', A. n.19M.

Seel) Leslie Frazer F11-et VAssistentcemmieeienexor Patente.

